1. Field of the Invention
This invention is related to thermosetting powder coating compositions and in particular to compositions containing epoxy resins.
2. Description of the Prior Art
Epoxy resin powder coating compositions are well known, as shown by U.S. Pat. No. 3,028,251 issued Apr. 3, 1962 to Nagel; U.S. Pat. Nos. 3,338,863 and 3,645,960 issued Aug. 29, 1967 and Feb. 29, 1972, respectively, to Haag. However, these powder coating compositions do not meet the approval of the Food and Drug Administration (FDA) for food contact use, such as for protective coatings for food and beverage containers. Epoxy powder compositions of Pregmon U.S. Pat. No. 3,882,064 issued May 6, 1975 have FDA approval for food contact use but are not adequate for use in steel containers for highly acidic foods such as tomato products or juices.
Therefore, there remains a need for a powder coating composition which is approved for food contact and which is adequate for use with acidic foods.